Operational direct current systems (ODCS) based on LFP batteries

LFP-based ODCS are structurally organized along the same lines as standard lead-acid ODCS. The difference in the use of the basic storage element brings the benefits of higher energy and power storage density, less maintenance required, long service life (up to 20 years) and advanced monitoring and self-diagnosis system provided by the applied battery management system.

In particular, the benefits lie in the following aspects:

1. Low internal resistance. Ability to deliver large inrush current

Due to high discharge currents, significantly exceeding the currents that lead batteries of similar capacity can provide, especially for a short period of time (up to 15 s, up to 5 minutes, up to 30 minutes), the use of ODCS and LIA (lithium-ion battery) can be beneficial in the presence of high inrush currents .

In this case, when designing the ODCS on the lead-acid battery, a battery with a much larger capacity than necessary is forced to be laid, which leads to an additional increase in the budget - both directly for the battery and for the surrounding infrastructure.

ODCS with LIA is able to provide the necessary power parameters with a compact LIA cabinet of relatively small capacity.

2. High energy storage density

Due to chemical features, the energy storage density in LIA is several times higher than that for lead-acid battery. In this regard, a large lead-acid battery can be replaced by a more compact LIA cabinet, which frees up a significant area.

At the same time, LIA does not require special infrastructure, like lead-acid battery, it can be located in any electrical room

3. Possibility of locating ODCS in the immediate vicinity of the load

In connection with the previous point, it is also important to reduce the length of cable lines due to the placement of ODCS near the load. This gives both a direct economic effect (reducing the length of the cable) and a hidden one (losses and voltage drops on the cable are reduced, it is possible to simplify and reduce the power of the required system)

4. Possibility of implementing (n+1) redundancy scheme

The design and principle of operation of the LIA allow for the parallel connection of several batteries. In combination with compact dimensions, this makes it possible, when designing, to lay down, where necessary, the possibility of redundancy according to the n + 1 scheme instead of 2n - a non-alternative scheme when using lead-acid battery.

5. Easy maintenance

LIA, like any electrical equipment, requires regular maintenance. Conventionally, all the necessary procedures can be divided into 2 parts: typical and special.

Typical activities include activities that are typical for any similar equipment: broaching of contacts, dust removal, etc.

Special operations are required due to the specifics of lithium-ion batteries. These include, for example, conducting a charge / discharge cycle, analyzing emergency protocols and a report from an automatic self-diagnosis system.

However, the LIA is designed in such a way that the system can perform most of the special operations on its own with minimal participation of personnel. The total maintenance volume of LIA is much lower than the procedures with lead-acid battery.

6. Information support

ODCS with LIA in comparison with classical ODCS with lead-acid battery (however, with most of the ODCS on other lithium-ion batteries) provides the user with a fundamentally different level of information support and analytics.

Thus, in the archive part of the UARS (archiving, registration and service unit is an element of the SUAB KOMBAT battery management system) information is stored that allows you to restore the work schedule of the SOTS for any period of operation, to trace the dynamics of changes in any parameter of both the battery as a whole and each battery.

One of the difficulties when working with a lithium-ion battery is the problem of diagnosing its condition. From a simple degree of charge (the classic method - the NRC voltage is not suitable, the battery characteristic has almost the same voltage in the range of 15-85% charge) to values characterizing the physical state of the battery.

SUAB KOMBAT uses specially developed proprietary algorithms that allow:

• provide 3 balancing modes;
• automatically determine the internal resistance, leakage currents (self-discharge), the degree of degradation of each battery during operation;
• control the resource of each battery.

In addition, the software capabilities of the UARS module make it possible to transfer this information both to any dispatching system and broadcast it to remote devices - for example, a PC and phone application.

These properties make it possible to apply the principle of predictive repair - the depletion of a resource or the occurrence of other technical problems can be predicted before they occur and take proactive measures.